Process of making paints



Nov; 1 l, 1930. H. H. MAPOTHER, JR 1,781,643

PROCESS OF MAKING PAINTS Filed Nov. 17; 1928 INVENTOR. Hf/V/FY M MAPOTHEK Jr.

ATTORNEY Patented Nov. 11, 1930 UNITED STATES PATENT'OFFICE HENRY H. momma, JR, 01' IIBOIITIS'V'IIJLE, KENTUCKY, ASSIGNOB TO 388 CORPORATION, A CORPOBATIOLI OF KENTUCKY vacuum racc- Application nled'liovembei- This invention relates to a process of making paints by means of sub ecting the dry contents or pigments to a vacuum and then adding the liquid constituents or vehicles while the former is continued to be subjected to a vacuum and has for its objects; first, to render the process more expeditious and at an 'ap recia ly less cost; second, to produce paint y eliminating the present day practice of grinding the pigments in oil after the pigments have been produced in their usual way.

By the term paint I refer to a liquid or vehicle usually composed of oils and volatile spirits, drying or oxidation, into which there is dispersed one or more base and inert pigments, generally or: mineral origin, which have been previously ground to practically im alpable powders, added in a quantity only su cient to render the vehicle opaque and hide or cover the surface on which it has been spread for the, purpose of reserving the surface, preventing corrosion, or decoration or for a combination of these functions.

lhe pigments or dry contents are prepared in commercial form in a powdered condition, a mass of which necessarily carries with it a high percentage of air which fills theinterstic'es formed between the irregular surfaces of the particles.

The existing methods of manufacturing paint call for a preliminary mixing of the pigments and vehicles in dough or lead mix ers 1n order to get the two sufiiciently incorporated for grinding. The grindin of paint is merely to effect the complete i'spersion of the pigment particles in the oil or other liquid that constitutes the vehicle. The grinding is done on various well known types of mills.

In my new process 1 eliminate the major part of this old involved method by employing a vacuum to remove the moisture and air from a mass of pigment thus reducing the surface tension and increasing the capillary attraction, or as it is customarily termed the wetting characteristic of the pigment. The

. introduction of the vehicle is therefore foligment and lowed by a rapid mixing of completely vehicle by which the former 1s 17,, 1828. Serial No. 320,094.

taken up in suspension with a minimum of occluded gases. In a corresponding degree the necessity for extended grinding 1s avoided as the dispersion of pigment in vehicle is in part accomplished by the condition of vacuum maintained at the time of mixing the details of the process will be understood incon- .junction with apparatus described vhereiln and represented by the drawin s, in which:

Figure 1 represents a-modi ed pebble mill carried on valve equipped hollow shafts mounted in suitable bearings. The cylinder (1 is provided with an opening 1 communicating with the outside and is arranged so as to be hermetically sealed with lid 6, gasket 6 and bolts 0, o. llhe hollow shafts d, d' are carried in bearings d (P; The valves '0 and '0 are attached to shaft a? and rotated with same.

In Fig. 2, I have shown a standard "container f, the top of which is open. Superimposed is a dome g, the major opening of which is so co-related to container 7 that by means of gasket h, a hermetically sealed joint may be affected when the screw 71, carried in bracket j is forced downward by means of lever a. In the dome are openings Z and m, the former being arranged for communication. to a vacuum pump and the latter for the admission of liquid.

In using the apparatus shown in Fig. 1, I place a predetermined quantity of pigments in the mill with valve 0 closed and c in c0mmunication with a vacuum pump. The cover his secured in place and the vacuum drawn. At this stage a predetermined quantity of liquid material is admitted through valve 1), both valves are now closed and their connections removed, so as to allow the mill to be rotated by means of pulley n. The pebbles in this mill effect a complete dispersion. This is of particular use where a relatively large portion of liquid to dry content is employed. As a means of reducing the time period necessary for the mill to efiect a complete dispersion, with certain formulas, I apply air pressure through valve 41 after'the milling I vEL carried in external containers, a portion of the dry content is placed in container and then a portion of the liquid content 15 applied after the vacuum has been drawn. This is repeated until the predetermined quantities have been treated in the container.

I employ this stage process to efiect a rapid and complete (penetration of the pigment with the liqui This latter process is of particular use in the manufacture of low priced goods such as paste and, semi-paste,

} as it eliminates very considerably wastage of material, labor and apparatus employed. A clear conception of my invention will be had when it is considered that the pigment is in the form of minute particles having a maximum of surface area. The interstices between the particles are filled with air and thus resistant to the introduction of Y the liquid vehicle. By reducing the air pressure and thus rarifying the air by means of a vacuum, the liquid vehicle may be caused more readily to flood the mass of pigment particles which latter are thus dispersed in the liquid. The articles of pigment are found to, remain in suspension to a greater degree by reason of the manner in which.

they have caused to disperse through the vehicle.

Many variations from the a paratus illustrated and described are possi le, as well as the various steps in the process herein em ployed and described, therefore, I do not wish to be limited other than by the appended claims.

I claim:

1. The rocess of mixing paint which consists in su jecting the fine y ground dry pi ments to a vacuum, mixing a liquid vehic e with the said pigments which have been subjected to the vacuum and uniformly dispersing the pigments in the vehicle while maintaining the vacuum.

2. The process of mixing paint which consists in treating the dry ingredients by reduction of atmosphere pressure, then mixing a liquid vehicle with the said dry ingredients while subject to the reduction of pressure, and maintaining the pressure reduced while the vehicle substantially wets the entiresurface of the ingredients.

3-. The'process of makin a paint from a dry powdered pigment an a liquid vehicle, whic includes the steps of removing oci'. eluded gases from the interstitial spaces between the pigment particles b means of a vacuum-bringing together sai dry pigment particles and the liquid vehicle while maintaining said vacuum, whereby the liquid fills 60 said interstitial spaces, and efiecting the dispersion of the pigment particles in the liquid vehicle by thorough mixing.

In testimony whereof I aflix my signature.

. HENRY H. MAPOTHER, Jn. 

